1. Field of the Invention
The present invention relates to semiconductor devices and storage devices provided therewith. More particularly, the present invention relates to a semiconductor device with a built-in flash memory, and a storage device provided therewith.
2. Description of the Background Art
As the storage capacity of flash memories increases, they have recently been used as external storage devices for portable information systems by taking advantage of their higher resistance to vibration compared with hard disc devices and the like. However, the product specification of flash memories varies from one company to another, which makes it difficult to directly connect them to the portable information systems.
In order to solve this problem, the PCMCIA-ATA (Personal Computer Memory Card International Association-AT Attachment) method has been employed as an example. PC cards, CompactFlash.TM. and the like based on the PCMCIA-ATA method (hereinafter, referred to as ATA cards) have the same unit of data rewriting as hard disc devices because emulation of a hard disc device is carried out in ATA cards.
Thus, the ATA cards can be accessed similarly to hard discs.
In order to maintain the comparability, it is necessary that the cards have a built-in ATA controller LSI. Thus, the price of an ATA card is increased. To reduce the price of an ATA card, one-chip ATA controllers with a built-in flash memory are being developed which are each formed by integrating a flash memory and an ATA controller LSI on one chip.
The ATA card is typically formed of a flash memory, an ATA controller LSI for flash memory control and management, and peripheral circuitry. The card storage capacity is determined by the number of connected flash memories which can be controlled by the ATA controller LSI.
By forming an ATA controller LSI and a flash memory, which has been externally connected, so that they are built in one chip, the number of components provided on the ATA card can be reduced. Thus, ATA card size reduction and cost reduction can be made possible.
FIG. 7 is a block diagram showing a construction of a conventional one-chip ATA controller 100.
Referring to FIG. 7, one-chip ATA controller 100 includes a built-in flash memory 114, and an ATA controller portion 102 to transmit/receive data between a host system and built-in flash memory 114.
ATA controller portion 102 includes a host interface 103 which is formed of an interface based on the PC card standard, including a data bus 10B to transmit/receive data to/from the host system and a plurality of control signals CSIG, a CPU 106 which receives an interrupt signal IRQ for reading and writing requests from host interface 103 and controls ATA controller portion 102, an ROM 116 which stores a program executed by CPU 106, an RAM 118 which transmits/receives various data for program execution to/from CPU 106, a sequencer 108 which controls various circuits according to an instruction from CPU 106, a flash I/F circuit portion 110 which is controlled by sequencer 108 and outputs a necessary control signal to built-in flash memory 114, and a buffer memory 112 which serves as a data buffer when data is transmitted/received between host interface 103 and built-in flash memory 114.
In the construction of conventional one-chip ATA controller 100 shown in FIG. 7, however, the capacity of a built-in flash memory is the storage capacity of the ATA card. In order to implement memory cards, for example, which include various storage capacities according to application, it is necessary to develop and produce a plurality of one-chip ATA controllers each having a built-in flash memory of different storage capacities.
In general, semiconductor devices lose mass production cost merits as the number of types increases. Thus, the effects of cost reduction achieved by one-chip formation are not sufficiently obtained.